An Overview of Metabolism and Biochemical Energy ADP and ATP are phosphoric acid anhydrides O a Contain linkage in carboxylic acid anhydrides React with alcohols by breaking a P-O bond and forming a phosphate ester,ROPO32-.The reaction is a nucleophilic acyl substitution at phosphorus Phosphorylation reactions with ATP require the presence of divalent metal cation in the enzyme,usually Mg2+,to form a Lewis acid-base complex with the phosphate oxygen atoms and neutralize some negative charge H 0 Adenosine Adenosine ATP Mg2+ 00 B-O-P-0+ OPOP-O-Adenosine +Mg2+ A phosphate ester ADPADP and ATP are phosphoric acid anhydrides ▪ Contain linkages analogous to the linkage in carboxylic acid anhydrides ▪ React with alcohols by breaking a P-O bond and forming a phosphate ester, ROPO3 2- . The reaction is a nucleophilic acyl substitution at phosphorus ▪ Phosphorylation reactions with ATP require the presence of divalent metal cation in the enzyme, usually Mg2+,to form a Lewis acid-base complex with the phosphate oxygen atoms and neutralize some negative charge An Overview of Metabolism and Biochemical Energy